Early detection of precancerous changes in various organs in the human body may improve results of treatment and ultimately save lives. Techniques used to detect such changes include visual endoscopy and collection of tissue samples (i.e., biopsy) at predetermined sites that are typically used to analyze tissue of organs for abnoinial changes.
As an example, tissue of the esophagus may be examined using light scattering spectroscopy. Esophageal adenocarcinoma is a form of cancer the incidence of which is increasing rapidly in the United States. Almost 100% of cases of esophageal adenocarcinoma occur in patients with Barrett's Esophagus (BE), an otherwise benign condition in which metaplastic columnar epithelium replaces the normal squamous epithelium of the esophagus.
Although the prognosis of patients diagnosed with adenocarcinoma may be poor, the chances of successful treatment increase significantly if the disease is detected at the dysplastic stage. Once BE has been identified in a patient, the patient may be enrolled in an endoscopy/biopsy surveillance program, presuming that the patient is a candidate for surgery should high-grade dysplasia be detected. The surveillance of patients with BE for dysplasia may be challenging in at least three respects. First, dysplasia may not be visible during routine endoscopy. Thus, known testing techniques often require that numerous biopsy specimens be taken at random locations along the patient's esophagus for histopathologic examination of the excised tissue. Second, the histopathologic diagnosis of dysplasia is problematic because there is poor interobserver agreement on the classification of a particular specimen, even among expert gastrointestinal pathologists. Third, reliance on the histopathologic examination imposes a time delay between endoscopy and diagnosis, which may severely limit the diagnostic accuracy of the endoscopic procedure.